Model Assets and Loading

Hardware and Software Integration

This page covers Wuji Hand 2.2 model assets, root links, and loading models in MuJoCo, ROS 2, and Isaac Sim.

• Root link: {l,r}_mount is the arm flange mount (69 g), shared by the URDF, MJCF, and USD models. The wrist shell is fixed to it through {l,r}_wrist_fixed
• Actuator naming: {l,r}_{THJ|FFJ|MFJ|RFJ|LFJ}{0-3}, with the anatomical naming map in the Joint Table

Use the URDF definition as the source of truth for the relationship between the wrist mounting frame and root link. The model formats and available CAD assets ship with the wuji-description repository. For the palm mounting interface STEP and A3 dimensioned drawing, see Mechanical Integration.

Model Assets

This page uses the model directories and package names introduced in wuji-description v2026.10.12.

Rigid-body models that include the soft-pad geometry are available. Deformable-body simulation isn’t supported yet.

The models include the arm flange mount and no longer provide a separate _with_mount variant.

Models are named wujihand2_2-{side}, and the USD entry point is wujihand2_2.usd.

Requirements

Get and Load

git clone https://github.com/wuji-technology/wuji-description.git
cd wuji-description

MuJoCo:

# Right hand
python -m mujoco.viewer --mjcf=hand2/hand2_2/body/mjcf/right.xml

# Left hand
python -m mujoco.viewer --mjcf=hand2/hand2_2/body/mjcf/left.xml

MJCF collision geometry is the convex hull of each link mesh. The 27 links with meshes participate in collision, with 15 body pairs excluded by the model configuration, so inter-finger and fingertip-to-palm contacts stay live. Display layers are group 1 visual, group 2 collision, and group 3 fingertip sites.

For dependencies, description packages, and launch commands, see ROS 2 Integration.

Isaac Sim USD:

The USD is a layered asset with base, physics, robot, and sensor sublayers plus the logo texture. Keep the complete contents of each usd/{left,right}/ directory. The root prim is wujihand2_2_{side}. Drive gains hold the current pose when you select Play.

URDF preview requires Rust/Cargo. See the urdf-viz installation guide.

URDF preview:

cargo install urdf-viz
urdf-viz hand2/hand2_2/body/urdf/right.urdf

Verify

1. Confirm MuJoCo or the URDF viewer opens with no missing meshes
2. Confirm the model shows 20 revolute joints
3. Confirm the directory and ROS 2 package name match 2.2

Loading the model confirms that the assets, paths, and visualization pipeline work. Firmware, networking, sensors, and real device control need a connected device to verify.